掺杂锰的氧化锌纳米线中电场控制的铁磁性。

Electric-field control of ferromagnetism in Mn-doped ZnO nanowires.

机构信息

Device Research Laboratory, Department of Electrical Engineering, University of California , Los Angeles, California 90095, United States.

出版信息

Nano Lett. 2014;14(4):1823-9. doi: 10.1021/nl404464q. Epub 2014 Mar 5.

DOI:10.1021/nl404464q

PMID:24564741

Abstract

In this Letter, the electric-field control of ferromagnetism was demonstrated in a back-gated Mn-doped ZnO (Mn-ZnO) nanowire (NW) field-effect transistor (FET). The ZnO NWs were synthesized by a thermal evaporation method, and the Mn doping of 1 atom % was subsequently carried out in a MBE system using a gas-phase surface diffusion process. Detailed structural analysis confirmed the single crystallinity of Mn-ZnO NWs and excluded the presence of any precipitates or secondary phases. For the transistor, the field-effect mobility and n-type carrier concentration were estimated to be 0.65 cm(2)/V·s and 6.82 × 10(18) cm(-3), respectively. The magnetic hysteresis curves measured under different temperatures (T = 10-350 K) clearly demonstrate the presence of ferromagnetism above room temperature. It suggests that the effect of quantum confinements in NWs improves Tc, and meanwhile minimizes crystalline defects. The magnetoresistace (MR) of a single Mn-ZnO NW was observed up to 50 K. Most importantly, the gate modulation of the MR ratio was up to 2.5 % at 1.9 K, which implies the electric-field control of ferromagnetism in a single Mn-ZnO NW.

摘要

在这封信件中，展示了通过背栅式掺锰氧化锌（Mn-ZnO）纳米线（NW）场效应晶体管（FET）实现的对铁磁性的电场控制。通过热蒸发法合成了 ZnO NWs，然后在 MBE 系统中通过气相表面扩散工艺进行了 1 原子%的 Mn 掺杂。详细的结构分析证实了 Mn-ZnO NWs 的单晶性，排除了任何沉淀物或次生相的存在。对于晶体管，场效应迁移率和 n 型载流子浓度分别估计为 0.65 cm2/V·s 和 6.82×1018 cm-3。在不同温度（T=10-350 K）下测量的磁滞回线清楚地表明了室温以上的铁磁性。这表明 NW 中的量子限制效应提高了 Tc，同时最小化了晶体缺陷。在高达 50 K 的温度下观察到了单个 Mn-ZnO NW 的磁电阻（MR）。最重要的是，在 1.9 K 时，MR 比的栅极调制高达 2.5%，这意味着在单个 Mn-ZnO NW 中实现了铁磁性的电场控制。